Synthesis and Bilayer Characteristics of Single Chain Ammonium Amphiphiles Containing Diphenyl Sulfide Unit

Novel single-chain amphiphiles which contain diphenyl sulfide (DPS) chromophores were synthesized. Methyl substituents were introduced to various positions of the aromatic rings. Electron microscopy and differential scanning calorimetry (DSC) measurements confirmed the formation of stable bilayer membranes from all of the amphiphiles. Gel-to-liquid crystalline phase transition as well as the ehromophore interaction in bilayer aggregates were significantly influenced by the number and position of methyl substituents. Introduction of the alanine residue into the amphiphile effectively improved the membrane stability and promoted development of the aggregate structure, due to the hydrogen-bond formation. It was possible to control the molecular orientation by methyl substituents on the rigid segment.